Air-gas mixture metering device, notably for respiratory mask

ABSTRACT

A device providing a predetermined mixture of atmospheric air and oxygen to a respiratory mask includes a first chamber responsive to pulses of oxygen and a second chamber, which provides the output to the mask, which is responsive to the first chamber. A mixing chamber is provided and is constructed such that although the ratio of atmospheric air and oxygen provided to the mask may vary, the total amount of mixture remains at a predetermined value.

United States Patent Metivier Aug. 20, 1974 [54] AIR-GAS MIXTURE METERING DEVICE, 3,068,857 12/1962 Black l28/l45.8 NOTABLY FOR RESPIRATORY MASK 3,429,326 2/1969 Arnell et a1. 137/98 3,537,450 11/1970 Fox 128/145.6 Inventor: Robert fi Pans, France 3,605,785 9/1971 1901,1111... 137/98 Assigneez Societe Minerve Courbevoie, 3,664,361 5/1972 Bartels 137/98 France FOREIGN PATENTS OR APPLICATIONS 22 il June 9 1972 604,704 9/1960 Canada 137/63 1 PP N05 263,772 Primary Examiner-Wi1liam R. Cline Assistant ExaminerGeorge L. Walton [30] Foreign Application Priority Data Attorney, Agent, or Firm-Gottlieb, Rackman,

June 22, 1971 France 71.22657 Relsman K'rsch 52 us. 01 137/625.41, l28/145.8, 137/88, [57] ABSTRACT 137/6254 A device providing a predetermmed mlxture of atmo- 51 1111. C1 Fl6k 11/00, 005d 11 /02 spherie air and oxygen to a respiratory mask includes [58] Field of Search 128/1455, 145.6, 145.7, a first chamber responsive to pulses of oxygen and e 23 453 3 37 133 93 0 07, second chamber, which provides the output to the 254 25 41; 251/206 207 mask, which is responsive to the first chamber. A mixing chamber is provided and is constructed such that 5 R f n Cited although the ratio of atmospheric air and oxygen pro- P vided to the mask may vary, the total amount of mixture remains at a predetermined value. 2,969,789 1/1961 Morch 128/145.8 3,045,668 7/1962 Lee 128/1455 6 Claims, 2 Drawing Figures a 1 \\2\ g l a z //s: 113 7714; 32 Z 21 a 33 Z K i 5b6w436a65 11 21 1 11 L A 19 22 f 9 \s\\\ V4 23 j 7// AIR-GAS MIXTURE METERING DEVICE, NOTABLY FOR RESPIRATORY MASK FIELD OF THE INVENTION The present invention relates in general to metering devices and has specific reference to a device for proportioning a mixture of air and another gas under pressure, notably oxygen, more particularly for supplying a respiratory mask.

BACKGROUND OF THE INVENTION In this particular application it was current practice heretofore to use a source of compressed air and a source of compressed oxygen, these sources supplying a mixing device through a pair of control valves permitting the separate adjustment of the outputs of the two gases, with the assistance of a pair of outputmeters, in order to keep the total output of the gaseous mixture substantially independent of the proportioning thereof. It is obvious that a metering arrangement of this character is relatively delicate and slow to control, since it implies the actuation of two separate adjustment members, notably valve means, while constantly endeavouring to keep at a constant value the sum of the output values displayed.

SUMMARY OF THE INVENTION It is a first object of the present invention to provide a proportioning device requiring only one source of compressed oxygen as far as it utilizes atmospheric air for constituting the desired final gaseous mixture.

It is another object of this invention to provide means for proportioning a gaseous mixture by controlling a single adjustment member the actuation of which is substantially without any influence on the total output of the resultant gaseous mixture which remains substantially constant.

It is a complementary object of this invention to provide a proportioning device of the type set forth hereinabove, which comprises a first chamber and a second chamber, separated by at least one deformable or movable partition, the first chamber being connected to the outlet of an automatic respirator producing a pulsated flow of oxygen under pressure, the other chamber being connected on the one hand directly to an inlet or feed pipe of the respiratory mask and on the other hand through a non-return valve to a constant-output adjustable mixing device/comprising an atmospheric air intake and an oxygen intake connected in turn to the first chamber through a valve the closing of which is controlled in synchronism with the pulsated oxygen flux produced by the respirator.

According to a particularly advantageous form of embodiment of the device of this invention, the second chamber aforesaid consists of a bellows suspended from an upper inner wall of the first chamber and weighted at its bottom portion; while the constantoutput adjustable mixing device comprises a mixing chamber of which one wall element has a relatively great number of small holes formed therethrough, these holes having preferably the same dimensions, and an adjustable distributor for delivering the air and oxygen flows from the corresponding intakes, respectively, to first and second sets of holes formed in said wall element, comprising first and second variable numbers of holes, respectively, of which the sum is preferably constant.

BRIEF DESCRIPTION OF THE DRAWING By way of example, a typical and preferred form of embodiment of the proportioning device according to the present invention is illustrated diagrammatically in the attached drawing and will now be described in detail. In the drawing:

FIG. 1 is a vertical section taken along the median or center line of the device, and 7 FIG. 2 is a plan view from above showing a detail as seen at II-II of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT The specific form of embodiment of the present invention which is illustrated in the attached drawing comprises essentially a body 1, preferably of suitable metal or alloy, having formed preferably centrally or its upper portion a cylindrical bore 2 having a vertical axis AA. The bottom of this bore 2 provides a mixing chamber 3 of which the top wall element comprises a partition disc 4 bearing with its circular edge on a shoulder 5 of bore 2. As shown in FIG. 2, this disc 4 has formed therethrough a relatively great number of holes 6a, 6b disposed on two concentric circular arcs centered to said axi AA. In the example illustrated each circular row of holes 6a, 6b comprises 20 small holes of same dimensions notably of the same diameter and same relative spacing. A cylindrical drum 7 is engaged in said bore 2 so as to rotate freely therein, with its lower face urged against the top face of disc 4 by a coil compression spring 8 reacting against a plug 9 threaded in a tapped portion of the bore 2. A stem 10 rigid with drum 7 extends through said plug 9 formed to this end with a suitable hole, and the outer end of said stem 10 carries a knurled knob 11 whereby the drum 7 can be rotated in said bore 2. The lower face of drum 7 has formed therein a pair of distributor chambers 12 and 13 in the form of a pair of segments of circular rings of the same angular amplitude, disposed symmetrically to the axis AA and shown in FIG. 2, the two distributor chambers 12 and 13 have a radial width slightly greater than that of the two circular rows of holes 6a and 6b of disc 41 and the lengths of these chambers are equal and correspond substantially, in the example illustrated, to half the length of each one of the circular rows of holes 6a, 6b. Known means (not shown) are provided to hold the disc 4 against rotation in the bottom of bore 2 and to limit the permissible rotation of drum 7 about the axis AA between two end positions. In one position, none of the holes 60, 6b register with one of said chambers 12 or 13, and in the other position a maximum number of holes, for example 20, register with the other chamber 13 or 12. FIG. 2 corresponds to one of the intennediate positions of drum 7, and in each such positions its chambers 12 and 13 register with first and second groups of holes 6a, 6b, respectively, comprising first and second variable numbers of these holes, of which the sum is constantly the same and notably equal to 20, irrespective of the intermediate position contemplated.

Drum 7 defines two annular grooves, l4, 15 formed in its cylindrical side surface which communicate with the aforesaid distribution chambers 12 and 13 respectively via passages 16 and 17 formed through the drum 7. Beneath the body 1 and detachably secured thereto for example threadly, is a cup or casing 18 forming a first chamber. The chamber is connected via a passage 19 and a pipe 20 of said body 1 and also via a preferably flexible hose (not shown) to the outlet 21a of an automatic respirator 21 producing a pulsated flow of oxygen under pressure. The present invention is not strictly limited by the use of a specific type of automatic respirator of this character, of which various types are known in the art; one of them is disclosed in my US. Pat. No. 3,614,965 for Five-port bistable pneumatic valve unit. In the first chamber 18 a bellows 22 weighted at its lower portion 23 is suspended from the lower end of said body 1 thereby defining a second chamber consisting of the inner space of this bellows 22. The second chamber communicates with the mixing chamber 3 formed in said body 1 via a passage 24 formed in the lower portion of said body 1 which passage includes a non-return valve 25. The inner space of bellows 22, forming said second chamber, is connected directly to a respiratory mask (not shown) via a passage 26 formed in the lower portion of body 1, a pipe 27 fitted in said body 1 and a preferably flexible hose (not shown), in which an air filter is preferably inserted.

Whatever the angular position of drum 7 about the axis AA, the open faces of its annular peripheral grooves and 14 register with first and second, constantly open atmospheric air intakes, respectively, passages 28 and 29 formed in said body 1. The second atmospheric air intake 29 also connects to an oxygen passage such as 30 leading into the annular groove 14 of drum 7, passage 30 is formed in the body 1 so as to open into the first chamber 18, and has a valve inserted therein. This valve consists essentially of a lateral chamber 31 inserted in said passage 30. Within chamber 31 is a seat 32 and a flexible membrane 33 normally somewhat spaced from said seat 32 but adapted to engage and close seat 32 when an overpressure is exerted on the face of membrane 33 which is opposite to said seat 32. In the example illustrated, this overpressure is produced in the corresponding portion of chamber 31 via a pipe 34 for connecting a portion of chamber 31 to a source of pressure pulsated in synchronism with the oxygen flow produced by the respirator 21. By way of example, the pulsated pressure on membrane 33 is provided from an auxiliary outlet 21b which provides pulses in synchronism with the oxygen flow delivered through main outlet 21a.

The above-described device according to this invention operates as follows:

Each pulsated oxygen flow produced by the respirator 21 increases the pressure in the first chamber 18 due to the latter being isolated from the second atmospheric air intake 29 by the engagement of membrane 33 with its seat 32 caused by the synchronous pulses provided at pipe 34. The pressure increment in said first chamber 18 is attended by the compression of bellows 22. This causes valve 25 to close and the contents of the bellows is thus forced towards the respiratory mask via passage 26 and pipe 27. During the time period subsequently elapsing from this first pulsated oxygen flow to the next flow, the membrane 33 resumes its position of equilibrium illustrated in FIG. 1, in which it is spaced from the seat 32, and the oxygen under pressure in the first chamber 18 escapes partly through the second atmospheric air intake 29 and partly through the annular groove 14 of drum 7. The fraction of this oxygen which penetrates undertlfese conditions into the bellows 22 notably via passage 16 and mixing chamber 3, and also through the then open non-return valve 25, depends on the number of holes 6a, 6b of disc 4 which register with said chamber 12 and therefore on the angular position or setting of drum 7. Likewise, the amount of atmospheric air drawn through passage 28, annular groove 15, passage 17 and chamber 13 of drum 7, as well as through the mixing chamber 3 and nonreturn valve 25, due to the expansion of bellows 22 caused by its weight 23, is also subordinate to the angular position of said drum 7. However, the total amount of air and oxygen delivered to the bellows 22 is independent, of the angular position of drum 7 since, on the one hand, the total number of holes 6a, 6b fed simultaneously from the two distributor chambers 12 and I3 is constantly the same, and these holes 6a, 6b have the same dimensions. Therefore, the mass of the air and oxygen mixture contained in the bellows 22, which is subsequently forced towards the respiratory mask during the next pulsated oxygen flow, is substantially independent of the angular position of drum 7, whereas the proportions of air and oxygen constituting this gaseous mass are directly subordinate to this position, so that the drum control knob 11 may be provided with an index or pointer 35 registering with a corresponding graduation or scale (not shown) displaying for example the oxygen percentage and carried by the top surface of body 1.

The device of the present invention can be embodied in many different ways without departing from the basic principle of the invention. Thus, more particularly, the first and second chambers may be designed in many different manners, provided that they are separated by at least one deformable wall such as a membrane or a movable wall, such as a piston, so that any pressure increment in the first chamber is attented by a reduction in the volume of the other chamber. The constant-output adjustable mixing device to which the second chamber is connected via a non-return valve may also be embodied in many different ways, some of which may be known, outside the one illustrated. Even the illustrated mixer lends itself to many different modifications as will readily occur to those conversant with the art. Thus, instead of rotatably mounting the cylindrical drum 7 in the body 1, this drum could be locked against rotation therein, and in this case the stem 10 of control knob 11 is connected to the perforated disc 4 adapted to rotate in the bore of body 1. Instead of having the distributor chambers 12 and 13 and the holes 6a, 6b of wall element 4 of mixing chamber 3 in mutual contact on a flat interface, these chambers and holes could be caused to engage each other along a cylindrical interface; in this case, the distributor chambers 12 and 13 may be formed either in a central cylindrical member or in an annular member surrounding said central member, and the adjustment rotation may be imparted either to said central member or to the annular member surrounding same. The number, dimensions and relative arrangement of the holes 60, 6b and the arrangement and dimensions of the distributor chambers, 12 and 13 are also optional. Instead of being of rotational character, the relation movement produced between the members in which said distributor chambers and the holes of the wall element of the mixing chamber may be obtained for example by producing a movement of translation. Finally, the valve inserted in the oxygen intake connecting the adjustable mixing device to the first chamber may be of one among many different and possibly known types outside the type illustrated, so that the properly pulsated pressure of a fluid is used more or less directly for controlling the closing and opening movements of the valve member.

The proportioning device of this invention is particularly suited for artificial respiratory apparatus designed for long service periods, notably for new-born children.

What is claimed is:

1. A device connectable to atmospheric air and a pulsated stream of another gas for generating a pulsated stream of a proportioned mixture of atmospheric air and another gas which comprises a first chamber having an inlet for receiving the pulsated stream of said other gas; a second chamber having an inner volume variable between a maximum and a minimum value, and having an outlet; means sensitive to the increasing pressure in said first chamber for decreasing the volume of said second chamber to its minimum value, means for restoring said second chamber volume to its maximum value when the pressure in said first chamber has decreased; a mixing chamber having a first inlet for the atmospheric air, a second inlet for said other gas, and an outlet; means coacting with said first and second inlets for adjusting the ratio of the volumes of air and said other gas admitted in said mixing chamber; a first passage inserted between said second inlet and said first chamber; a normally open valve inserted in said first passage; pressure sensitive valve closing means influenced by the pressure of the pulsated stream of said other gas to close said valve; a second passage inserted between the outlet of said mixing chamber and said second chamber; and a non-return valve disposed in said second passage to close said second passage whenever the volume of said second chamber is decreased so that the air-gas mixture contained in said second chamber is expelled through its outlet.

2. A device as set forth in claim 1, wherein said mixing chamber has a wall consisting of a perforated plate with at least one row of small holes of same dimensions and disposed at regular intervals defined therein, said holes being aligned in a predetermined direction; and said air-gas ratio adjusting means further comprises a movable body having one face in fluid-tight contact with the face of said plate which is opposite to said mixing chamber, first and second elongated cavities being formed in said one face of said body, said cavities having a same extent in said direction and opening into the small holes of said plate, passages being formed in said body for connecting the atmospheric air inlet and the other gas inlet to said first and second cavities respectively, and means for moving said body and said plate in relation to each other, from a first end position, in which none of the holes of said plate register with said first cavity, and a plurality of holes register with said second cavity, to a second end position, in which none of said holes register with said second cavity, and a plurality of holes register with said first cavity;

3. Device as set forth in claim 2, wherein said small holes formed in said plate are disposed along at least one circular arc, the body and the perforated plate being mounted for relative rotation concentrically to said circular arc.

4. Device as set forth in claim 3, wherein said body is a drum having one end face in contact with said perforated plate.

5. Device as set forth in claim 1, wherein an outlet opening into the free atmosphere is connected to said first passage, downstream of said valve.

6. Device as set forth in claim 1, wherein said pressure sensitive means for decreasing the volume of the second chamber consists of a bellows suspended in said first chamber, and said means for restoring said second chamber volume to its maximum value consists of a weight attached to the lower portion of said bellows, said second chamber consisting of the inside volume of said bellows. 

1. A device connectable to atmospheric air and a pulsated stream of another gas for generating a pulsated stream of a proportioned mixture of atmospheric air and another gas which comprises a first chamber having an inlet for receiving the pulsated stream of said other gas; a second chamber having an inner volume variable between a maximum and a minimum value, and having an outlet; means sensitive to the increasing pressure in said first chamber for decreasing the volume of said second chamber to its minimum value, means for restoring said second chamber volume to its maximum value when the pressure in said first chamber has decreased; a mixing chamber having a first inlet for the atmospheric air, a second inlet for said other gas, and an outlet; means coacting with said first and second inlets for adjusting the ratio of the volumes of air and said other gas admitted in said mixing chamber; a first passage inserted between said second inlet and said first chamber; a normally open valve inserted in said first passage; pressure sensitive valve closing means influenced by the pressure of the pulsated stream of said other gas to close said valve; a second passage inserted between the outlet of said mixing chamber and said second chamber; and a non-return valve disposed in said second passage to close said second passage whenever the volume of said second chamber is decreased so that the air-gas mixture contained in said second chamber is expelled through its outlet.
 2. A device as set forth in claim 1, wherein said mixing chamber has a wall consisting of a perforated plate with at least one row of small holes of same dimensions and disposed at regular intervals defined therein, said holes being aligned in a predetermined direction; and said air-gas ratio adjusting means further comprises a movable body having one face in fluid-tight contact with the face of said plate which is opposite to said mixing chamber, first and second elongated cavities being formed in said one face of said body, said cavities having a same extent in said direction and opening into the small holes of said plate, passages being formed in said body for connecting the atmospheric air inlet and the other gas inlet to said first and second cavities respectively, and means for moving said body and said plate in relation to each other, from a first end position, in which none of the holes of said plate register with said first cavity, and a plurality of holes register with said second cavity, to a second end position, in which none of said holes register with said second cavity, and a plurality of holes register with said first cavity.
 3. Device as set forth in claim 2, wherein said small holes formed in said plate are disposed along at least one circular arc, the body and the perforated plate being mounted for relative rotation concentrically to said circular arc.
 4. Device as set forth in claim 3, wherein said body is a drum having one end face in contact with said perforated plate.
 5. Device as set forth in claim 1, wherein an outlet opening into the free atmosphere is connected to said first passage, downstream of said valve.
 6. Device as set forth in claim 1, wherein said pressure sensitive means for decreasing the volume of the second chamber consists of a bellows suspended in said first chamber, and said means for restoring said second chamber volume to its maximum value consists of a weight attached to the lower portion of said bellows, said second chamber consisting of the inside volume of said bellows. 